Arcam AB (AMAVF)

Clobbered on Tuesday thanks to Stratasys' warning and soft 2015 guidance, 3D printing stocks are up sharply amid a market rally (the Nasdaq is up 0.7%). 3D Systems (DDD+4.8%), Stratasys (SSYS+7.3%), Voxeljet (VJET+3.8%), ExOne (XONE+4%), and Arcam (OTCPK:AMAVF+5.1%) are among the gainers.

Possibly helping the group: 3D modeling/simulation software firm Dassault and industrial prototyping services firm Proto Labs have each soared after posting Q4 beats. Though each firm only gets a fraction of its revenue from 3D printing/additive manufacturing use cases, they've each occasionally been hyped as 3D printing plays.

Gabelli recently made a contrarian call on 3D Systems and Stratasys, upgrading the printer makers following the latter's warning. The firm argued 3D's shares have "limited downside" at an enterprise value of 14.8x estimated 2016 EBITDA, and praises Stratasys' "extensive product and service portfolio and its focus on high-value business applications."

Organovo (ONVO-4.2%), Proto Labs (PRLB-5.4%), and Arcam (OTCPK:AMAVF-4.9%) have joined 3D Systems, ExOne, and Voxeljet in selling off in the wake of Stratasys' Q4/2014 warning and light 2015 guidance.

Proto Labs is far from a 3D printing pure-play - the company is a custom-parts maker for industrial prototyping, one that supports 3D printing and other manufacturing techniques. Organovo, as a developer of 3D-printed human tissues, is a very different kind of 3D printing firm than the printer makers.